Extreme pressure lubricant



Patented Dec. 24, 1940 EXTREME PRESSURE LUBRICANT Darwin E. Badertscher, Woodbury, Francis M.

Seger, Pitman, and William H. James, Woodbury, N. J., assignors to Soeony-Vacuum Oil Company, Incorporated, New York, N. Y., a corporation of New York No Drawing. Application October 3, 1939,

Serial No. 297,672

12 Claims.

withstanding the enormous pressures encountered between engaged surfaces in various types of modern machinery such as the hypoid gears used in motor vehicles. This fact has led to the development of the so-c'alled extreme pressure lubricant, which is comprised of a suitable carry- 20 ing agent such as ahydrocarbon oil containing a minor proportion of an ingredient which under the extreme pressures encountered will provide or form between the engaged surfacesa lubricating film capable of withstanding these high pres- 25 sures. Ingredients of the type just referred to are known as extreme pressure agents or extreme pressure (E. P.) bases, and numerous materials 7 have been proposed for such use. Among the various E. P. bases which have been proposed and 30 which have met with varying degrees of success are metal soaps, certain compounds of sulfur and certain classes of compounds containing sulfur and chlorine. Phosphorus compounds have also been proposed, as well as compounds containing 35 phosphorus and nitrogen.

The present invention is'predicated upon the discovery of a novel class of compounds containing phosphorus and sulfur and which may contain phosphorus, sulfur and chlorine, which when added in minor proportion to a suitable carrying medium, such as a hydrocarbon oil, will impart to such carrying medium outstanding extreme pressure characteristics. More specifically;

the compounds or reaction products contemplated 5 by this invention are obtained by reacting a halide of phosphorus with an alkali thiocarbonate.

The halides of phosphorus which may be employed as the first reactant mentioned above are typified in the chlorides by phosphorus trichloride 50 (P013), phosphorus pentachloride (PCls), phosphorus oxychloride (POCls) and phosphorus sulfochlorlde (PSClz) As the alkali thiocarbonate we prefer to use such thiocarbonates which have been derived prlsed only of a petroleum fraction is incapable of trative of these compounds may be'mentioned the alkali alkyl monothiocarbonates and the alkali alkyl dithiocarbonates or alkali alkyl xanthates and alkali alkyl ,trithiocarbonates.

We are aware of the fact that the esters of 5 the acids of phosphorus have been proposed and have been used with varying degrees of success as extreme pressure lubricant bases, and we therefore make no claim to the esters of the acids of phosphorus. The compounds of the present invention' are distinguished from the esters of the acids of phosphorus in that they are mixed anhydrides of phosphorus acids and the organic,

or more specifically, the aliphatic, thiocarbonic acids. The molecular composition of the products obtained by reacting halides of phosphorus with alkali thiocarbonates will vary not only with the reactants used but also with the molecular proportions of such reactants. For example, where one molecular proportion of phosphorus trichloride is reacted with three molecular proportions of an alkali alkyl trithiocarbonate, all of the chlorine in the P013 combines with the alkali metal of the thiocarbonate to effect a substitution of three alkyl thiocarbonate groups on the phosphorus. Run the other hand, only two or only i one molecular proportion of the thiocarbonate is used with one molecular proportion of the phosphorus halide mentioned, one or two atoms respectively-.of the chlorine will remain in the in which X represents sulfur or oxygen; m represents the number of X atoms in the molecule represented by the formula and is equal to zero or 1; n represents the number of chlorine atoms and is equal to zero, 1 or 2 Y represents sulfur or.

oxygen; and R represents an aliphatic hydrocar- 5'0 bon radical.

Illustrating the application of the foregoing general formula, if one molecular proportion of:

phosphorus oxychloride is reacted with two molecular proportions of an alkali alkyl dithio-' carbonate such as potassium ethyl xanthate, the product of such reaction has the probable fornlllla.

( SC OCIHB I general formula:

The details in the procedure which may be followed in preparing the reaction products contemplated herein as extreme pressure lubricant bases will be best understood from the following examples in which various phosphorus halides have been employed and in which the reactants have been employed in various proportions. It will be observed in all of these examples that potassium ethyl xanthate is the thio-carbonate reactant but, as indicated above, the invention contemplates thiocarbonates other than the dithiocarbonate or xan-thate and alkyl groups other than the ethyl group, such for example, as the propyl, butyl, amyl, etc. 5

EXAMPLEI PREPARATION OF PRODUCT FROM POTASSIUM ETHYL XANTHATE AND Pnosrnorms TRICBLORIDE IN MOLECULAR Pnoroizrrons or THREE TO ONE A solution of 24 grams P013 in 100 cc. acetone was added to 71 grams recrystallized (potassium ethyl xanthate) in 400 cc. of acetone during 34-minutes with stirring and at a temperature of 0 to +3 C. After stirring for 80 minutes longer at; room temperature, the mixture was suction-filtered to remove the inorganic reaction salt (KCl) and the filtrate concentrated by distillation at a liquid temperature of not over 0., under vacuum. The residue, a light brown, .mobile liquid, weighed 41.5 grams. The product contained phosphorus, sulfur and a trace of chlorine and may be considered as a mixed anhydrideof an alkyl (ethyl) xanthic acid and an acid of phosphorus.

AND Pnosrrronus TRICHLOBIDE IN MOLECULAR PROPORTIONS or Two TO ONE Eighty grams of recrystallized KS.CS.OC2H5 were added gradually to a solution of 34 grams P013 in 500 cc. acetone during 45 minutes, with stirringand at a temperature of 22 to' 32 F. The mixture was then left over-night at a temper-arture of 70-75 F. and worked up asin the preceding experiment, yielding 127 grams of a brown, mobile liquid with a fairly pleasant odor, resembling that of mesityl oxide. The product, which contained phosphorus, sulfur and chlorine, was a mixed anhydride of ethyl xanthic acid and phosphorus acid, such mixed anhydride containing chemically combined halogen (chlorine).

EXAM? LE 3 REACTION Paoouc'r or PoTA'ssIUM ETHYL XANTHATE AND Pnosrnonus SULFOCHIORIDE IN MOLECULAR PBDPOBTIONB or Tamra TO. ONE

To 55 grams of recrystallized KS.CS.O'C2H5 in 300 cc. acetone was added, with stirring, a. solutionof 19-19.5 grams PSCls in 100 cc. acetone during 22 minutes at a temperature of from -2 to 3 C. The mixture was stirred 35 minutes longer at room temperature and then worked up as in the preceding experiment, yielding 33 grams of a mobile, brown liquid. The product, containing phosphorus, sulfur and a trace of chlorine, may be considered to be a mixed anhydride Of ethyl xanthic acid and thiophosphoric acid.

EXAMPLE4 REACTION PRODUCT or POTASSIUM ETHYL XANTHATE AND PHOSPHORUS SULFOCHLORIDE IN MOLECULAR PBOPORTIONS or Two r0 ONE ing 86 grams of mobile, dark brown liquid. The

product contained phosphorus, sulfur and chlorine and was a mixed anhydride of ethyl xanthic acid and thiophosphoric acid, such mixed anhydride containing chemically combined halogen (chlorine).

EXAIHPLE '5 REACTION PRODUCT or- Por.ss1mr ETHYL XANTHATE AND PHOSPHOBUS OXYCHLORIDE IN MOLECULAR PBOPORTIONB or THREE 'ro ONE Fifty-eight grams KS.CS.OC2H5 were added with stirring to a solution of 15.5 grams POC13 in 200 cc. CS: during 30 minutes. at a temperature of 0 to 5 C. The temperature was then held at 40-45 C. for an hour and at 30-40" C. for 4 hours additional. The reaction mixture was then allowed to stand over-night, after which it was filtered and. worked up as in the preceding experiment, yielding 28 grams of mobile light yellow liquid. The product, a mixed anhydride of ethyl xanthic acid and phosphoric acid, contained phosphorus, sulfur and a trace of chlorine.

To demonstrate the effectiveness of the materials contemplated by this 'invention as extreme pressure lubricant ingredients we have prepared and tested compositions comprised of the reaction products prepared under the foregoing examples as the E. P. ingredients and mineral oil as the carrying agent. The mineral oil used was one having a Saybolt viscosity of from to seconds at 210 F. and the reaction products from the examples described above were added thereto in amounts of 5 per cent. Examples of these extreme pressure lubricant blends were sub- Jected to the Almen pin test described by Wolf and Mougey, Free. A. P. I., 1932, pages 118-130, and the S. A. E. test, described in S. A. E. Journal 39, 23-4 (1936). These two tests are commonly" accepted in the art as standards to determine From the foregoing examples it will be seen that the phosphorus halide-thiocarbonate reaction products or mixed anhydrides of alkyl thiocarbonic acid (specifically alkyl xanthic acid) and acids of phosphorus contemplated by this invention are highly efiicient extreme pressure lubricant bases. The amount of these materials which may be used to give a satisfactory extreme pressure lubricant may be varied from about 1 per cent to about 20 per cent, but in general amounts in the neighborhood of 5 per cent are preferred.

Although we have indicated from the foregoing description that a. mineral lubricating oil is a preferred carrying agent for the extreme pressure ingredients contemplated herein, it is not our intention that the invention be limited to any particular carrying or blending medium, but the invention includes broadly extreme pressure lubricants containing these reaction products dissolved, dispersed or emulsified, in any other suitable carrying medium, such for example as fatty, vegetable or animal oils; light petroleum hydrocarbons such as kerosene, etc.; benzene and related hydrocarbons; alcohols; esters; others,

etc.

We claim: 1

1. An extreme pressure lubricant composition comprising a mineral lubricating 011. containing as an extreme pressure ingredient the mixed anhydrides or an alkyl thiocarbonic acid and an acid of phosphorus characterized by the general formula Y I x.Pc1.(s d-YR in which X and Y represent elements selected from the group consisting of sulfur and oxygen; m represents the number of X atoms in the molecule and is equal to zero or one; n represents 55 the number of chlorine atoms in the molecule and is equal to zero, one or two; and R represents an aliphatic hydrocarbon radical. r

2. An extreme pressure lubricant composition comprising a hydrocarbon oil and a small propor- 50 tion of an extreme pressure base comprised of mixed anhydrides of an alkyl thiocarbonic acid and an acid of phosphorus. I

3. An extreme pressure lubricant composition comprising a hydrocarbon oil and a small propor- 5 tion of an extreme pressure base comprised of 70 portion of extreme pressure base comprised of halogen-bearing mixed anhydrides of an alkyl thiocarbonic acid and an acid 01' phosphorus.

5. An extreme pressure lubricant composition comprising a hydrocarbon oil and a. small proportion of extreme pressure base comprised of a halogen-bearing mixed anhydride of alkyl xanthic acid and an acid of phosphorus.

6. A lubricant composition comprising a hydrocarbon oil and a small proportion of mixed anhydrides 01 an alkyl thiocarbonic acid and an acid of phosphorus, said mixed anhydrides having been obtained by the reaction of a halide of phosphorus with an alkali alkyl thiocarbonate.

7. A lubricant composition comprising a hydrocarbon oil and a small proportion of mixed anhydrides of an alkyl thiocarbonic acid and an acid of phosphorus, said mixed anhydrides having been obtained by the reaction of a halide of phosphorus selected from the group consisting of P012. PCls, POCI: and PSC13 with an alkali alkyl thiocarbonate.

8. A lubricant composition comprising a hydrocarbon oil and a small proportion of mixed anhydrides of an alkyl thiocarbonic acid and an acid of phosphorus, said mixed anhydrides having been obtained by the reaction of a halide of phosphorus selected from the group consisting 01' P013, PCls, P001; and PSCI: with an alkali alkyl thiocarbonate selected from the group consisting of alkali alkyl monothiocarbonates, alkali alkyl dithioearbonates and alkali alkyi trithiocarbonates.

9. A lubricant composition comprising a hydrocarbon oil and in admixture therewith from about one per cent to about twenty per cent of mixed anhydrides of an alkyl thiocarbonic acid and an acid of phosphorus, said mixed anhydrides having been obtained by the reaction of a halide of phosphorus selected from the group consisting of P013, PCls, POCi; and P801; with an alkali alkvl thiocarbonate selected from the group consisting of alkali alkyl monothiocarbonates, alkali alkyl dithiocarbonates, and alkali alkyl trithiocarbonates. V

10. A lubricant composition comprising a hydrocarbon oil and a small proportion of mixed anhydrides or an alkyl xanthic acid and an acid of phosphorus, said mixed anhydrides having been obtained by the reaction or about one molecular proportion of a halide of phosphorus with from about two to about three molecular proportions of an alkali alkyl xanthate.

11. A lubricant composition comprising a hydrocarbon oil and a small proportion of mixed anhydrides of ethyl xanthic acid and an acid of phosphorus, said mixed anhydrides having been obtainedby the reaction of about one molecular proportion of a halide of phosphorus with from about two to about three molecular proportions of an alkali ethyl xanthate.

12. A lubricant composition comprising a hydrocarbon .oil and in admixture therewith from about one per cent to about twenty per center mixed anhydrides of ethyl xanthic acid and an" DARWIN E. BADERTSCHER. FRANCIS M. SEGER. WILLIAM H. JAMES. 

